In recent years legislation has been providing stricter regulation over the emission of contaminants into the atmosphere. In most instances governmental standards rigidly control the concentration of pollutants to within stringent limits. The economic impact of such control on certain industries has been severe. In some situations factories have been forced to close their doors and cease operations because conformance to the new regulations has involved complete replacement of elaborate production equipment or has involved introducing procedures that were not economically feasible. For example, a Federal regulation promulgated in 1974 stipulates that within a prescribed time period, concentrations of vinyl chloride monomer (VCM), a suspected carcinogen, in industrial atmospheres must not exceed one part per million, a requirement so stringent as compared with existing practice that many firms have projected complete plant shutdowns with consequent idling of thousands of employees. By means of the present invention, atmospheric emissions containing certain environmental pollutants in light or heavy concentrations become drastically decontaminated through improved photochemical oxidation procedures.